Abstract: A vat paper machine is disclosed, the machine including a cylinder-vat unit having a rotatable cylinder mold, a vat and a headbox for providing a continuous supply of stock to the vat. The vat has a special wall structure and is arranged upstream of the cylinder mold in such a manner that the wire gauze covered cylinder mold is brought into contact with stock in the vat to form a web by draining water from the stock through the wire gauze covered surface of the mold. An outer wire is also provided which runs in a loop over a breast roll, through the vat at the wall structure thereof and then over and around a portion of the circumference of the cylinder mold. The wall structure comprises an endless liquid-impervious belt forming an endless loop located on the inner side of the loop defined by the outer wire.

Abstract: A vat paper machine is disclosed, said machine including a cylinder-vat unit having a rotatable cylinder mold, a vat and a headbox for providing a continuous supply of stock to the vat. The vat is arranged upstream of the cylinder mold in such a manner that the wire-covered cylinder mold is brought into contact with stock in the vat to form a first web by draining water from the stock through the wire-covered surface of the mold. An outer wire is also provided which runs in a loop over a breast roll, through the vat along its bottom wall and then over and around a portion of the circumference of the cylinder mold. The portion of the bottom wall of the vat which is located between the breast roll and the cylinder mold includes a platform supporting the outer wire. The platform is provided with slit means that form one or more drainage passages which serve to form a second web on the outer wire.

Abstract: The invention relates to a method and an apparatus for detecting and counteracting a deformation of the stock discharge gap in a paper machine headbox, which is caused by thermal expansion due to the temperature of the stock and/or the pressure of the stock. This is achieved by ultrasonic transducers located close to the slice opening which obtain measurement results relating to the distance between the roof member and the apron beam member of the headbox. At least two such transducers, one preferably located close to a side wall of the discharge gap and the other preferably located midway between the side walls, give information about a possible difference between the measurement results caused by the deformation. This difference serves as a guide for adjusting the temperature of the apron beam member and/or the roof member in such a way that the deformation is reduced in magnitude or entirely eliminated.

Abstract: Multilayer headbox apparatus for a papermaking machine comprises spaced apart headbox walls defining an elongated, converging channel terminating in an exit opening, and at least one partition member anchored in the headbox at its upstream end with its downstream end free, said partition member extending from side to side in the headbox and at least to the vicinity of said opening and dividing the headbox into a plurality of shallow, converging channels extending to said opening for conveying a plurality of paper making stocks thereto and for discharging a plurality of paper making stocks therefrom in stacked, spaced apart relation, together with means for maintaining a wedge-shaped body of gaseous fluid between said discharged jets at the downstream end of said partition member to keep the jets separated for a predetermined distance beyond said exit opening in the direction of a forming surface.

Abstract: A method for forming a multilayer jet by delivering a plurality of superposed, spaced apart jets of stock through a slice opening towards a web forming zone, keeping the jets separated for part of the distance between the slice opening and the forming zone, and thereafter, but not later than the arrival of the jets at the forming zone, allowing the jets to come into direct contact to produce a stratified jet. Separation of the jets in this fashion is effected by forming and maintaining gaseous wedges in the spaces between them after delivery through the slice opening.

Abstract: Stock flow alignment means for the headbox of a paper machine or the like comprises a plurality of composite tubes having their opposite ends mounted in apertures in two spaced apart tube plates extending in the cross machine direction. Each composite tube includes first and second tubular elements assembled in telescoping relation to accommodate changes in length resulting from thermal expansion. Also, each composite tube is formed with a stepwise enlargement of its cross section in the direction of flow near the telescoped ends of the tubular elements. Flow deflector means disposed in the flow paths to the inlet ends of the composite tubes prevent fibers in the stock from collecting at the inlets.

Abstract: Methods and apparatus for producing a web by injecting a jet of stock between two tensioned wires and running the wires over a circumferentially grooved forming cylinder. The cylinder grooves and a zone immediately on the other side of the wires extending from the forming throat where the web is injected to the web run-off point are in direct, open communication with the ambient atmosphere so that water is drained inwardly and outwardly of the forming cylinder as the web is being formed. The jet stock size, wire speed and wire tension are adjusted in relation to the radius of the forming cylinder so that the inward and outward drainage of liquid from the web occurs in relative amounts sufficient to avoid substantial two-sidedness of the web thus produced.